Research On Network Coding Based Multipath Transmission In Software Defined Fiber Wireless Access Networks

Fi Wi network combines the advantages of optical and wireless access have attracted a great deal of scholarly attention with the features of high capacity,high rate,good flexibility and low cost.The software defined network(SDN)with the architecture of decoupling the control plane from data plane and the characteristics of realizing network functions by the form of software is expected to become a new solution to the current network problems.Since the multipath transmission has changed the bottleneck of network in single path,but it also brings the problem of data packet disorder caused by split and regroup.The proposed network coding completely solves the problem of packet disorder in multipath transmission,at the same time,it also greatly improves the network throughput,improves the utilization of network resources,and realizes network load balancing.Therefore,we combine SDN and FiWi network to design a new software defined Fi Wi network architecture,and design NC based multipath transmission mechanism on it.The research results are as follows.(1)According to the structural characteristics of SDN and FiWi,we present the architecture of SD-FiWi networks.Based on this architecture,the infrastructure node construction and the controller which support the Openflow protocol,are designed in detail.Then we elaborate the process of data transferring between control layer and the infrastructure layer based on the Openflow protocol are described.(2)We propose a multipath transmission mechanism in SD-FiWi network.Through improving the controller and flow table of SD-FiWi network,we use time delay and packet loss rate as the routing criteria to realize the node disjointed multipath routing algorithm.Simulation results show that the mechanism can effectively improve the utilization ratio of network resources,improve network throughput and achieve network load balancing.(3)We have designed an NC based multipath transmission scheme in SD-FiWi networks architecture.Moreover,an dynamic adaptive algorithm to modify the redundant factors is adopted to determine the number of redundant packets.And we also proposed the idea of how to divide the encoded packets on the multi paths.Simulation results show that the proposed scheme can effectively reducing the number ofretransmission and improve the throughput of the whole SD-FiWi network.